Better without batteries?

The new DC immersion heater is fitted into the water tank, ready to take the 48v output from the hydro-electric turbine. Having wavered from the straight path for a while and toyed with the idea of batteries, I have returned. Batteries are hassle it seems; they need looking after and replacing, contain nasty chemicals, emit potentially explosive hydrogen gas, can be rapidly ruined by an incompetent user, and are hideously expensive: nearly two grand for my small system. I have not ruled them out for good, however. But I am for now setting up with a wonderfully simple system: a cable runs from the turbine to the immersion heater. That's it. No inverters, charge controllers, or monitoring systems. Of course there is no flexibility - the power will only heat water for our domestic hot water and space heating. There are also two concerns - one is that we will be in danger of boiling the water in our tank (unlikely), and the other is that the power will hardly make a dent in this mighty task (more likely).

In either event the system will need rethinking. But for now I am delighted and excited to be getting it up and running in such a clear and simple way. Those enchantingly passionate and geeky folk at Energy Systems and Design have finished the turbine now. It is on it's way.

hydro

The pipe is in, ready to take water from where the burn flows into the garden and carry it with building pressure all the way to the back of the byre. This is a fall of around 20 metres giving a pressure of 2 bar, or 30 PSI in old money. With a flow rate of 8 litres per second (about average for the Camnacar burn) this should provide a constant 800 watts, through the Streamengine. I have plumped for this solid little turbine despite, or perhaps because of it's relative expense. Buy cheap, buy twice (and live with second rate rubbish all the while)! I have a friend already dissatisfied with his second cheap far-eastern turbine.
Hopefully the Streamengine will live up to my expectations. Eccentric Canadian enthusiasts are currently putting one together to meet the demands of our system. Directing jets of water at the bronze wheel are four nozzles, each one controllable so we can make the most of the variable flow of the burn. When it's a a trickle then perhaps just one will be turned on. After rain or snow melt all four valves will be open, and water will still be pouring over and past the intake. This could be seen as an enormous amount of wasted power, but it is not worth designing the system around the sort of flows that are only available for a small proportion of the year. I hope I have pitched it about right with 110mm diameter pipe and 1.5 kW turbine. Time will tell.
To begin with I will direct the output to our 200 litre thermal store via an immersion heater and see how far it goes towards providing hot water and heating for the house. The way we use the power I expect to evolve over time. I don't yet have a grip on what this sort a wattage could usefully do for us. That the stream flows more strongly in the winter is ideal as our energy needs are very much greater then.  Of course space and water heating is the greatest demand, and even with a wood stove and boiler running more or less constantly the kerosine boiler does much of the work. Hopefully the turbine will begin to make the kerosine redundant. Within five years I would like to see that back of that system altogether. Securing a bigger and better supply of firewood and creating more space to season it will help. There is no substitute for well seasoned wood.
I will post more as the hydro system comes together.